<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<title>Document</title>
	<style type="text/css">
	 .box{
	 	width: 300px;
	 	height: 100px;
	 	background-color: #888;
	 }
	 .box p{
	 	height: 50px;
	 	background-color: red;
	 }

	</style>
</head>
<body>
	
	<div class="box">
	 <p></p>
	</div>
</body>
</html>